I didn't replace it because it was Sunday and I figured it out too late to get it. My X has 100,000 miles on it (2001). The inner boot was still strong. If you can get one I would do it for 30 to 40 bucks. You have to buy the grease anyway and the grease is in the kit. But if it is too late don't replace it just go to an auto parts store they all should have the special grease.